Insulated secondary charges

Abstract

A means of increasing the velocity of projectiles using multiple charges ignited at different times to facilitate a sustained pressure pulse in the barrel is provided. The propellant charges are separated with one or more rigid barriers and ignited in series; igniting the propellant nearest to the projectile first and the propellant that is farthest from the propellant last. By timing the ignition of the charges a higher average pressure is sustained in the gun tube without risking a breach blow. After the peak pressure of the first propellant charge is reached the second propellant is ignited. The energy of the second propellant causes the pressure in the gun tube to fall more gradually. Thus the average pressure that acts on the projectile is safely increased. The following includes several methods of accomplishing this.

1. A projectile propulsion system comprising:
 a. a gun tube with an open muzzle end and a closed breech end; 
 b. a projectile; 
 c. one base charge adjacent to the projectile; 
 d. at least one booster charge; 
 e. at least one rigid mechanical barrier separating the booster charge and the base charge configured to provide pressure and heat isolation between adjacent charges;
 wherein said rigid mechanical barrier is configured to act as a rigid support and to protect the at least one of said booster charges from crushing forces; and 
 
 f. at least one piston that is configured to act as a valve between the charges by sliding in an axial direction and wherein the piston is slidingly attached to a support structure that is located at the breech end. 
 
     
     
       2. A projectile propulsion system as set forth in  claim 1  wherein the piston is configured to slide in an axial direction toward the breech when the pressure inside the breech is greater than the pressure outside the breech. 
     
     
       3. A projectile propulsion system as set forth in  claim 1  wherein the at least one rigid mechanical barrier is rigidly attached to the gun tube and configured to insulate the at least one booster charge from the base charge's pressure when the base charge is ignited. 
     
     
       4. A projectile propulsion system as set forth in  claim 1  wherein the piston is configured to be accelerated by the base charge providing a means for the booster charge to act as a traveling charge to further accelerate the projectile. 
     
     
       5. A projectile propulsion system as set forth in  claim 1 , comprising a mechanical means of limiting the motion of the piston to limit the axial excursion of the piston in the gun tube. 
     
     
       6. A projectile propulsion system as set forth in  claim 1 , wherein the system is configured to control the movement of the piston towards the breech so that an ignition time of the booster charge may be controlled. 
     
     
       7. A projectile propulsion system as set forth in  claim 1 , further comprising at least two booster charges and at least two rigid mechanical barriers. 
     
     
       8. A projectile propulsion system as set forth in  claim 1 , further comprising one or more additional booster charges disposed breech ward of the said at least one booster charge each separated by barriers. 
     
     
       9. A projectile propulsion system as set forth in  claim 1 , further comprising a firing order in which the base charge is initiated before any of the other charges, and in which at least one booster charge is initiated after the said base charge. 
     
     
       10. A projectile propulsion system as set forth in  claim 1 , wherein the system is further configured to integrate the projectile, the at least one booster charge, base charge, the at least one mechanical barrier, the support structure and an initiation system into one assembly to facilitate insertion of the assembly into a gun tube. 
     
     
       11. A projectile propulsion system as set forth in  claim 1  wherein the piston is configured to translate in an axial direction toward the muzzle when the pressure in the booster charge volume is greater than the pressure in the base charge volume, or towards the breach when the pressures are in equilibrium.